Victoria Azarenka of Belarus reacts during her women's singles quarter-final tennis match against Agnieszka Radwanska of Poland at the Australian Open 2014 tennis tournament in Melbourne January 22, 2014.  [Photo/Agencies]

MELBOURNE, Australia - Victoria Azarenka's 18-match winning streak at the Australian Open ended in an upset 6-1, 5-7, 6-0 quarterfinal loss to Agnieszka Radwanska on Wednesday, continuing the flow of stars tumbling out of the season's first major.

Fifth-seeded Radwanska ended her own streak of three consecutive quarterfinal defeats at the Australian Open with a stunning display of versatile shot-making that shocked and confused the big-hitting Azarenka.

The result means both defending champions were out in the quarterfinals - Novak Djokovic lost in five sets to Stan Wawrinka the previous night.

Azarenka's defeat followed the fourth-round exits of top-ranked Serena Williams and Maria Sharapova and leaves 2011 French Open champion Li Na as the only major winner remaining in the women's draw.

Radwanska next plays No. 20 Dominika Cibulkova, who won the last eight games in a one-hour, 6-3, 6-0 quarterfinal rout of No. 11-seeded Simona Halep.

Li, a two-time finalist in Australia, will play 19-year-old Canadian Eugenie Bouchard in the other semifinal.

Radwanska played drop shots and slices from the baseline, forcing Azarenka to come forward and then lobbing or passing her. She hit touch volleys with calm precision, and instinctively anticipated Azarenka's shots.

She didn't fall into big-swinging rallies against the second-seeded Azarenka, either, continually mixing it up and saving the power for when she needed it.

"She was aggressive. She was making everything. She was guessing right," Azarenka said. "I was just playing a little bit too predictably.